In front of the U.S.S. Wisconsin in Norfolk harbor, a coatless Mitt Romney named a tieless Paul Ryan as his vice presidential nominee.

Romney’s choice was not much of a surprise after he told NBC’s Chuck Todd on Thursday that he wanted someone with “a vision for the country, that adds something to the political discourse about the direction of the country. I mean I happen to believe that this is a defining election for America, that we’re going to be voting for what kind of America we’re going to have.”

This arguably describes some of the others mentioned as possible nominees, but it clearly fits Paul Ryan.

He doesn’t fit some of the standard criteria for vice president. He hasn’t won a statewide election, held an executive position or become well known nationally or even in much of Wisconsin.

But more than anyone else, more even (as impolite as it is to say) than the putative presidential nominee, Ryan has set the course for the Republican party for the past three years both on policy and in politics. From his post as Chairman of the House Budget Committee, he has made himself not just a plausible but a formidable national nominee by advancing and arguing for major changes in entitlement policy.

He has argued consistently that entitlement programs — Social Security, Medicare, Medicaid — are on an unsustainable trajectory. Left alone, they threaten to crowd out necessary government spending and throttle the private sector.

Few public policy experts, on the center-left as well as the right, disagree. But many politicians, certainly those in the Obama White House, shy away from confronting the entitlement crisis. Better to demagogue your way through one more election cycle and kick the can down the road.

What’s astonishing is that Ryan has convinced his fellow Republicans to follow his lead. Almost all House and Senate Republicans have voted for his budget resolutions. And they have included his proposal to change Medicare, for those currently under age 55, from the current fee-for-service system to premium-support, in which recipients will choose from an array of insurers, with subsidies to low earners.

Republicans rallied to the Ryan plan during the nomination contest. Newt Gingrich was lambasted for calling Ryan’s budget right-wing social engineering, while Mitt Romney over time moved to embrace the basic elements of Ryan’s budget and Medicare reforms.

Ryan campaigned enthusiastically for Romney in the Wisconsin primary and there was clearly a rapport between these two numbers crunchers. Romney would defer to Ryan to answer and has made a point of staying in touch with him after clinching the nomination.

As a numbers cruncher Romney surely recognizes that Ryan knows federal budget policy about as well as anyone. And the sometimes politically tone deaf Romney must admire Ryan’s ability, honed in hundreds of town meetings in his marginal congressional district, to explain his stands in a way that wins over ordinary voters.

Democrats have naturally attacked the Ryan plan as gutting Medicare and have produced an ad showing Ryan shoving a wheelchair-bound granny down a hill. They’re licking their chops at the prospect of running a Mediscare campaign against the Romney-Ryan ticket.

But it’s not clear that the Mediscare tactic will work when the issue gains great visibility, as it will from Ryan’s selection.

For Ryan and Romney can make the point — lost in the shuffle when this is a low-visibility issue — that their plan leaves the current Medicare system in place for current recipients and those over 55. Those who have made plans based on the present program can continue to rely on it.

But they can also make the point that their reforms are necessary in order to make sure Medicare is sustainable in the long run. Polls show that many voters under 55 doubt that they’ll ever get the Medicare and Social Security benefits they’ve been promised.

One more thing about Ryan, I think, appealed to Romney. He has already shown he cannot be intimidated by the most eminent opponent. Watch the video of Ryan’s five-minute evisceration of Obamacare at the president’s Blair House meeting. You can tell that Obama didn’t like it one bit.

He better get used to it. Obama’s side is relying on trash-talking ads. Romney’s selection of Ryan shows he wants a debate on whether America should follow Obama on the road to a European-style welfare state.